M. C. Rozo1, T. J. Ziemlewicz2, S. L. Best1, S. A. Wells2, M. G. Lubner2, J. Hinshaw1,2, F. Shi1, F. T. Lee2, S. Y. Nakada1, E. Abel1 1University Of Wisconsin School Of Medicine And Public Health,Department Of Urology,Madison, WI, USA 2University Of Wisconsin School Of Medicine And Public Health,Department Of Radiology,Madison, WI, USA
INTRODUCTION AND OBJECTIVES: Approximately 15-20% of incidental renal masses ≤4cm are benign tumors such as oncocytomas or lipid poor angiomyolipomas (AML), which can be managed non-surgically. Increasing utilization of small renal mass biopsy (SRMB) may reduce treatment of benign tumors, decreasing upfront costs and preserving renal function in untreated patients. The objective of this study is to evaluate if increasing SRMB utilization reduces surgical treatment and upfront (30 day) costs of care management for patients with benign small renal masses.
Methods: Clinical and pathologic data were reviewed from patients with incidental renal masses ≤4cm who were treated surgically and/or received SRMB from 2003-2015. Patients not considering surgery were excluded. Patients were divided into 2 cohorts (2003-2009 and 2010-2015) for analysis to reflect increased SRMB utilization at our institution since 2010. Institution specific Medicare costs for 2015 were used to calculate costs of surgery and biopsy in all patient cohorts.
Results: Of 437 patients with renal masses ≤4cm, SRMB was performed in 6% of 199 patients treated from 2003-2009 and 54% of 238 patients from 2010-2015. The rate of surgery for benign tumors from 2003-2009 was higher than 2010-2015, 19.7% vs. 12.3%, p=0.04. For patients treated without biopsy from 2010-2015, the benign surgery rate was 21.8%. From 2010-2015, 42 patients with benign tumors were identified using SRMB and avoided surgery (10 AML, 32 oncocytoma).
Given the upfront cost of $2,020.44 USD for ultrasound guided biopsy and $12,153.01 USD for partial nephrectomy, the cost of care per patient was calculated for each of the two cohorts.
The cost per patient in the 2003-2009 vs. 2010-2015 cohort was $12,274.85 USD vs. $11,094.98 USD. Increased biopsy utilization was associated with $1,179.86 (9.6%) cost savings per patient. For 2010-2015, increased use of biopsy saved $280,840 USD in estimated upfront treatment costs.
Conclusions: Pretreatment biopsy reduces surgery for benign tumors and decreases the upfront cost of care per patient by $1,179.86 USD. Increasing utilization of biopsy for small renal masses decreases overall treatment cost and preserves renal function in patients with benign tumors who avoid treatment.